1. Field of the Invention
The present invention relates to a gravity flow filter system incorporating one or more filter beds for filtering particulate matter from liquids, such as water for a municipal water supply, and including a self-contained backwash flow arrangement not requiring backwash pumps. More particularly, the present invention relates to a filter system in which a separate backwash chamber is provided within a main vessel structure for maintaining a quantity of backwash liquid for gravity flow of backwash liquid for periodic backwashing of the filter.
2. Description of the Related Art
Gravity flow filters having a plurality of filter cells for filtering liquids, such as water for municipal water supply systems, are well known. One example of such a filtering arrangement is illustrated and described in U.S. Pat. No. 3,134,735, which issued on May 26, 1964, to J. W. Greenleaf, Jr. That patent discloses a multiple cell filter system having an integral backwash arrangement including an external backwash channel. In that regard, the inventor discloses an arrangement involving a siphon-controlled backwash technique, which is disclosed in conjunction with a separate, but similar inlet siphon.
Another form of gravity filter incorporating multiple filter cells is disclosed in my U.S. Pat. No. 5,032,294, which issued on Jul. 16, 1991. That patent discloses a structural arrangement in which a centrally located effluent control chamber is provided, with provisions for backwashing with filtered water from adjacent filter cells or through the operation of a pumping system incorporating a motor-driven pump.
Although the prior art devices function reasonably well in their intended environments, it is desirable to provide a gravity filter system that can be readily used in rural areas, as well as in developing countries. Consequently, it is desirable to provide such a systems in which the need for backwash pumps, rate controllers, air compressors, and the like, is preferably minimized as much as possible, and possibly even eliminated, to reduce the dependence of the system upon outside power sources, and also to minimize the need for repair and maintenance of such ancillary equipment.
It is an object of the present invention to provide an improved gravity flow filter arrangement in which an integral, gravity-based backwashing arrangement is provided.